Former President George W. Bush arrives before the start of Trump's inauguration.

Doug Mills/The New York Times

Former President George W. Bush and former first lady Laura Bush arrive before the start of Trump's inauguration.

Doug Mills/The New York Times

People gather on the National Mall.

Olivier Douliery/Abaca Press/TNS

Members of the Mormon Tabernacle Choir wait to perform at the inauguration of Donald Trump as the nationu2019s 45th president.

Damon Winter/New York Times

Members of the Washington National Cathedral Choir before the inauguration of Donald Trump.

Damon Winter/New York Times

President Obama exits the Oval Office on his last morning as president before heading to the residence to host a tea and coffee reception with first lady Michelle Obama for President-elect Donald Trump and Melania Trump.

Stephen Crowley/The New York Times

Former House Speaker John Boehner gathers with others before the start of the inauguration.

Doug Mills/The New York Times

Protesters line the National Mall during President-elect Donald Trump's inauguration.

Todd Heisler/The New York Times

Police officers attempt to aid supporters of President-elect Donald Trump through protesters blocking an entrance to the inauguration.

Victor J. Blue/The New York Times

Hillary Clinton and former President Bill Clinton (obscured) arrive at the U.S. Capitol to attend the inauguration.

Ruth Fremson/The New York Times

Former Vice President Dick Cheney, in hat, with his wife, Lynne Cheney, arrive before the start of Donald Trump's inauguration.

Doug Mills/The New York Times

A Donald Trump supporter shows her inaugural ticket admission on the West front Lawn of the U.S. Capitol before the swearing-in ceremonies.

Olivier Douliery/Abaca Press/TNS

Jamie Bartbarger of Pittsburgh waits for a train at the Greenbelt Station as she makes her way to the inauguration.

Lloyd Fox/Baltimore Sun/TNS

Crowds of people wait to get through security on Inauguration Day.

Lloyd Fox/Baltimore Sun/TNS

Donald Trump supporters stand on the West front Lawn of the U.S. Capitol before the swearing-in ceremonies.

Olivier Douliery/Abaca Press/TNS

Donald Trump supporters stand on the West front Lawn of the U.S. Capitol before the swearing-in ceremonies.

Olivier Douliery/Abaca Press/TNS

Donald Trump supporters take pictures on the West front Lawn of the U.S. Capitol before the swearing-in ceremonies.

Olivier Douliery/Abaca Press/TNS

Protesters chant while waiting in line for security on Jan. 20 in Washington, D.C.

Lloyd Fox/Baltimore Sun/TNS

Jeff Bruce of Boston holds a sign while waiting in line for security.

Lloyd Fox/Baltimore Sun/TNS

U.S. President-elect Donald Trump arrives on the West Front of the U.S. Capitol.

Chip Somodevilla/Getty Images

First lady Michelle Obama and Jill Biden arrive before the start of Donald Trump's inauguration.

Doug Mills/The New York Times

First lady Michelle Obama arrives before the start of Donald Trump's inauguration.